[1]} and [2]} give intensities of He ii \(\) 1640 and \(\) 4686 respectively for the 1988-1989 International AGN Watch NGC 5548 campaign. The published measurements include contamination from other lines which have not been removed. In Figure 3 we show He ii \(\) 1640 and \(\) 4686 intensities observed within \(\pm 2\)  days.[1]} give fluxes measured with two different extraction routines. We used the fluxes found from the SIPS extraction since they give better consistency between closely-spaced observations. The expected intrinsic unreddened He ii \(\) 1640/He ii \(\) 4686 ratio of 8.5 is indicated by the diagonal dashed line. Since quantities plotted in Figure 3 and Figure 4 have errors in both axes, the fits are the ordinary least squares bisector (OLS bisector) advocated by [4]}. For display purposes, to emphasize that what matters is the slope, we have slightly reduced the He ii \(\) 4686 fluxes by \(10 \times 10^{-15}\)  ergs s\(^{-1}\)  cm\(^{-2}\)  to make the OLS-bisector line pass through the origin. The offset is unimportant; what matters is the slope. The slope of the OLS-bisector gives an observed mean \(\) 1640/\(\) 4686 intensity ratio of \(3.29 \pm 0.12\) . Comparison with the expected intrinsic ratio of \(8.5 \pm 1\)  gives a mean \(E(1640-4686)\)  of \(1.03 \pm 0.19\)  magnitudes. The estimated error includes the statistical error in the OLS-bisector slope and the estimated uncertainty in the intrinsic ratio (see [5]}).
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